UNDATED  (AP) -- Blinding snow is falling fast in southern Minnesota where 12 inches or more is expected to accumulate during a busy holiday travel period.

Officials warned residents to stay off the roads until the accompanying high winds die down. By early Wednesday, 8.7 inches of snow was already on the ground in Prior Lake, 7.8 inches at St. Paul and 7.5 inches In Eagan.

At Minneapolis-St. Paul International Airport, crews worked overnight to clear runways ahead of the busiest travel day before Thanksgiving. About 20 flights were delayed or canceled Wednesday morning out of dozens of flights.

Many school districts and universities, including St. Paul Public Schools, the University of Minnesota and University of St. Thomas canceled Wednesday classes as travel conditions deteriorated.